With the development of touch panel display the need to process thinner glass using Ultra-Short Pulse (USP) laser has increased. Beam shaping improves the process yield and quality but requires specific precautions when applied to USP laser due to high peak power and dispersion.
Bessel beams improve the quality of glass drilling and cutting due to the extended depth of field. We present Bessel beam generation using a reflective off-axis axicon giving a more stable beam compatible with scanning system and with a profile closer to theory. The characteristics of the beam and of the processed glass are described.
Multi-kilowatt Laser Beam Welding processes are facing new challenges: reducing the final parts weight and improving reliability to decrease the amount of discarded parts. Appropriate beam shaping enables those improvements by decreasing the process defects and by allowing welding of new types of materials and of thinner parts.
We describe here the design and the process test results of a fully reflective beam shaper laser head compatible with high-power lasers demands integrated on a robot. The high efficiency cooling permitted by a reflective design reduces focus shift. A mm-wide annular shape onto the processed part enables melt pool size control.
Multi-Plane Light Conversion (MPLC) is an innovative shaping technique which allows theoretically lossless complex beam shapes. The free-space reflective design is particularly well suited to Ultra-Short Pulse (USP) laser-based processes challenges. We demonstrate the system high stability over long processing times thanks to a mode cleaning feature.
Here we show micro-cutting and engraving tests carried out on stainless-steel and brass with a high power, industrial, USP laser having squared, and circular top-hat profile generated using MPLC technology. Thanks to the sharp edges of the profile, a sensible reduction of the taper and optimization of the overlapping is observed
The recent development of Ultra Short Pulse lasers has widely broadened the range of possibilities of laser material processing. Associated with a proper beam splitting it enables adding to the surface new properties by texturing it.
We present here a fully reflective three by three beam splitter compatible with high power up to 300W with 500fs pulses lasers. The process results are presented including the repeatability of the pattern, and the achievable ablation rate. The pattern is 15µm waist gaussian beams with 300µm pitch.
Compatibility with scanning system and F-theta lenses, enabling micro-processing throughput improvement, is described.
Generation of nano or micro-scale structures on materials surface enables new functions and properties, such as super-hydrophobicity by lotus effect, surface blackening by light trapping, modification of surface tribological properties, etc. which are in high demand for a wide variety of industrial fields. Amongst the surface functionalization techniques, Ultra-Short Pulse lasers have been proven to be a reliable tool to create Laser Induced Periodic Surface Structures (LIPSS). Exploitation of LIPSS for industrial purposes poses some key problems like up scaling over large area with high repeatability and high throughput. Beam shaping could be a key element to overcome these issues. Specific shapes, such as top-hat line shape, could enable at once uniform processing over large surface with the consequence to reduce the processing time. Multi-Plane Light Conversion (MPLC) is an innovative technique of beam shaping which allows theoretically lossless complex beam shapes with a high control over amplitude and phase. The free-space reflective design allows for high beam shaping quality whilst maintaining the ultra-short property of the laser pulses, which is not usually achievable through other beam shaping methods. Here we show the results obtained over Stainless-Steel using an industrial femtosecond laser with a tophat line of 30μm × 594 μm intensity profile generated using MPLC technology. The beam has been delivered over the Stainless-Steel surface with a galvo scanner and focused through an f -theta lens of 100 mm. Surface morphology has been investigated via SEM and the processing time has been compared to conventional round Gaussian Beams
The development of a multisensor optronic device requires Size, Weight and Power (SWaP), cost-effective and modular rangefinders while keeping a good range performance. We report on a fully fibered monostatic laser rangerfinder based on a one lens collimator used as the aperture of both the emission and reception channels. This has been possible thanks to the use of a diplexer.
This design makes the system compacter and achieves a 200g system weight. In addition to its low volume, the fully fibered architecture allows designing a building block rangefinder with the collimator sub-system on one side and the laser and electronics cards module on the other side. Both are linked up by only an optical fiber. This kit format enables the rangefinder to better fit in any available space in higher level systems such as gimbals and multi-function imagers. Besides, no alignment is needed, and no parallax error is possible: the alignment between channels is guaranteed by design over the whole range.
The emission/reception channels of the first prototype has a 28mm diameter 80mm focal length lens, and a 1.55μm 100μJ pulsed laser firing in a burst mode. The rangefinder is set in a class 1 configuration, and measures at 1Hz. The achieved Extinction Ratio is 30dB, which is equivalent to a range on NATO targets of 7km. The achieved ER being class 1M at 5Hz is even 32dB, which is equivalent to a range of 8.5km on NATO targets.
More configurations are reported in this article with their associated performance.
Today, it is commonly agreed that mid-range rangefinders (typical range: 10 km) based on fiber laser
technology, constitute the best trade-off between performance and reliability. But to intend to compete with
long-range devices and propose an alternative to bulk solid state laser systems, it is essential to increase
significantly their extinction ratio (ER) compared to the state of the art.
In this paper, we report on successive real-time statistical algorithms performed on 2 different fiber laser
rangefinders and the feasability to achieve an extinction ratio up to 45dB in an eye-safety burst mode. Based
on a bi-static architecture and equipped with a 38 μJ and 125 μJ, 10 ns pulse fiber laser, their intrinsic ER in
single-pulse emission has been measured respectively at 28 and 33 dB. A 45 mm optical aperture receiver
and a specially designed compact electronics complete the device. This alternative to solid-states systems
dedicated to long range application, represents then a cost-effective solution.
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